Safety headrest for a motor vehicle

ABSTRACT

A vehicle seat ( 1 ) as a head-rest ( 5 ) which is mounted for movement about a horizontal axis defined by a bar ( 7 ) depending arms ( 12 ) extend downwardly into the back of the seat and carry a pressure plate ( 13 ) at a position behind the torso of the occupant of the seat so that pressure applied to the pressure plate ( 13 ) will cause the head-rest ( 5 ) to move forwardly. The pressure plate ( 13 ) is pivotally connected ( 14, 15, 16, 17 ) to the arms ( 12 ) to enable the arrangement to pivot to the maximum extent in a situation where the rear part of the seat is rigid, for example if the seat is a rear seat in a motor vehicle.

[0001] THE PRESENT INVENTION relates to a safety arrangement, and moreparticularly relates to a safety arrangement incorporated in a vehicleseat.

[0002] It is known to use, in a vehicle, a seat which is provided with ahead-rest mounted on the back of the seat, the head-rests being adaptedto move forwardly in the event that a rear impact should occur toprovide protection for the occupant of the seat in order to minimise, orobviate whiplash injuries. Such a head-rest may be termed an “active”head-rest.

[0003] It has been proposed previously to provide an active head-restwhich is activated when the occupant of the seat is pressed into theback-rest of the seat, as a consequence of a rear impact situation. Sucha prior proposed arrangement incorporates a head-rest which is mountedfor pivotal movement about a horizontal axis adjacent the top of theseat, the head-rest being connected, by appropriate arms, to a pressureplate which is mounted within the back-rest of the seat. As the torso ofthe occupant of the seat is pressed into the back-rest of the seatduring a rear impact, the pressure plate is moved in a rearwarddirection, thus causing the head-rest itself to move forwardly, so thatthe head-rest is brought into a position immediately behind the head ofthe occupant. An arrangement of this type is shown in U.S. Pat. No.5,378,043.

[0004] This prior proposed arrangement is intended for use in the frontseat of a motor vehicle. Typically the front seat of a motor vehicle hasa back-rest formed from an inverted “U”-shaped frame, with appropriatespringing and padding filling the area between the parallel arms of theframe. Typically both the forward facing side and the rearward facingside of the back-rest are made to be soft and flexible so that the seatis not only comfortable for a person sitting in the seat, but also isnot uncomfortable for the knees of a person sitting in the seat behind.Thus, in the prior art arrangement, the pressure plate can moverearwardly relative to the inverted “U”-shaped frame when a rear impactoccurs.

[0005] In many vehicles, the rear part of the back-rest of a rear seatis constituted by a rigid panel. One reason for this is that typicallythe rear part of the back-rest of the rear seat forms an upright walldefining part of the boot or trunk. This wall must be sufficientlystrong to prevent any luggage present in the boot or trunk from enteringthe passenger compartment in a frontal impact situation. Also, in manycases the back-rest of the rear seat may fold downwardly, and then thepanel at the back of the back-rest forms part of a load-bearingplatform.

[0006] If a head-rest of the type described in U.S. Pat. No. 5,378,043were to be mounted in the back-rest of a rear seat, having a rigid rearpanel, the pressure plate would, in a rear impact situation, almostimmediately engage the rigid rear panel, and thus the head-rest wouldnot be moved sufficiently forwardly to prevent whiplash injuries.

[0007] Whilst it might be possible to make the back-rest “thicker”, thuscreating more space for movement of the pressure plate, carmanufacturers tend to prefer seats that are as thin and as light aspossible. Whilst one might contemplate providing a hatch in the rigidplate, adapted to open in the event of a rear impact, to allow thepressure plate to move rearwardly, it is very difficult to provide ahatch whilst still maintaining a rear panel for the seat, which is flat.A flat surface for the rear panel is important when the back-rest of therear seat is folded forwardly so that the panel forms a load-bearingplatform. Also, of course, if the boot or trunk of the vehicle is fullof luggage, luggage would be adjacent the hatch and would prevent thehatch from opening. It is to be understood that if the pressure plate islocated closer to the front surface of the back-rest of the seat, thepressure plate would prove to be uncomfortable.

[0008] The present invention seeks to provide an improved safetyarrangement.

[0009] According to this invention there is provided a safetyarrangement for a motor vehicle, the safety arrangement comprising ahead-rest, means to mount the head-rest for pivotal movement about apredetermined horizontal axis adjacent the upper part of the back-restof the seat, and depending means adapted to extend downwardly within theback-rest of the seat beneath the predetermined axis, and which carry apressure plate to be located within the back-rest at a position behindthe torso of an occupant of the seat, so that pressure applied to thepressure plate will cause the head-rest to move, the pressure platebeing pivotally connected to the depending means.

[0010] Preferably the depending means comprise parallel arms.

[0011] Conveniently the pressure plate is provided with an integrallocating element extending upwardly above the axis about which thepressure plate is pivotally connected to the depending means, thelocating element being releasably connected to the depending means.

[0012] Advantageously the locating element is connected to the dependingmeans by means of at least one spring clip.

[0013] Alternatively the locating element is connected to the dependingmeans by means of at least one frangible element.

[0014] Conveniently a locating element is arranged in association withthe pressure plate and the depending means in a position above the axisabout which the pressure plate is pivotally connected to the dependingmeans.

[0015] Preferably the locating element is deformable.

[0016] Preferably the means to mount the head-rest comprise asubstantially horizontal bar adapted to be mounted, by means ofbearings, on a frame within the back-rest of the seat, the axis of thehorizontal rod being the said predetermined axis, the head-rest beingconnected to the bar.

[0017] Conveniently the depending means are connected to and depend fromthe bar.

[0018] In one embodiment of the invention the rear of the back-rest isprovided with a rigid panel.

[0019] In order that the invention may be more readily understood, andso that further features thereof may be appreciated, the invention willnow be described, by way of example, with reference to the accompanyingdrawings in which:

[0020]FIG. 1 is a schematic side elevational view of a vehicle seatincorporating a safety arrangement in accordance with one embodiment ofthe invention,

[0021]FIG. 2 is a front view of the seat of FIG. 1,

[0022]FIG. 3 is a view corresponding to FIG. 1 showing the seat in analternate condition.

[0023]FIG. 4 is a schematic side elevational view of a vehicle seatincorporating. a safety arrangement in accordance with an alternativeembodiment of the invention.

[0024]FIG. 5 and FIG. 6 are views corresponding to FIG. 4 showing theseat in alternate conditions.

[0025] In the described embodiment of the invention a head-rest isprovided on a vehicle seat, and the head-rest is adapted to moveforwardly when there is a rear impact to reduce or obviate whiplashinjuries.

[0026] Referring to FIG. 1, a vehicle seat 1, intended for use in a rearseat, comprises a squab 2 and back-rest 3. The rear face of theback-rest 3 is in the form of a rigid panel 4. The back-rest 3 isassociated with a head-rest 5. The head-rest 5 is initially mounted inposition above the back-rest of the seat and is supported by a pair ofparallel support arms 6. The parallel support arms 6 are connected to apivotally mounted horizontal bar 7. The pivotally mounted bar 7 hasopposed ends thereof supported in bearings 8 which are mounted on ahorizontal frame member 9 located in the back-rest of the seat, thehorizontal frame member 9, together with two vertical parallel armmembers 10, 11, forming a substantially rigid inverted “U”-shaped framecontained within the seat.

[0027] Two further parallel arms 12 are also connected to the horizontalbar 7, the arms 12 depending within the back-rest of the seat. The lowerends of the arms 12 carry a pressure plate 13. The pressure plate 13 isprovided with upwardly extending lugs 14, 15, which each receive anoutwardly directed pivot pin 16, 17, carried at the lower ends of thearms 12. The pressure plate can thus pivot about the axis of theco-aligned pins 16, 17. In the described embodiment the pressure platecan only pivot in one pivotal direction from the initial position shownin FIG. 1. Pivotal movement in the opposite direction is prevented, forexample by a stop, a ratchet or equivalent device. The pressure plate 13incorporates an upwardly directed locating arm 18, which extendsupwardly between the parallel arms 12. The upper end of the locating arm18 is releasably connected to the arms 12 by releasable catches 19, 20,which may be spring catches, or which may be catches constituted byfrangible elements adapted to break when subjected to a predeterminedforce. One or more springs, or other resilient means (not shown), may beprovided to bias the head-rest to the “initial” position shown in FIG.1.

[0028] It is to be appreciated that when the seat is in ordinary use,the head-rest will be substantially stationary. However, when a vehiclein which the seat is mounted is subjected to a rear impact, the torso ofan occupant of the seat will move so that the torso is effectivelyforced into the back-rest 3 of the seat. The torso of the occupant willthen engage the pressure plate 13, and the combination of the pressureplate 13, the parallel arms 12, the horizontal bar 7, the arm 6 and thehead-rest 5, will pivot about the axis of the bar 7, the ends of the rod7 rotating within the bearings 8. The head-rest 5 will thus begin tomove forwardly.

[0029] The lower-most edge of the pressure plate 13 will strike therigid panel 4 provided at the rear of the back-rest 3. Continuingpressure applied to the pressure plate 13 by the torso of the occupantof the seat will cause the clips 19, 20 to be released so that the upperpart of the locating arm 18 is no longer connected to the depending arms12. The pressure plate is then free to rotate about the axis of theco-aligned pins 16, 17, in its single direction of pivotal movement. Ascan be seen from FIG. 3, this means that the pressure plate 13 willeffectively pivot about the axis of the pins 16, 17, and also its ownlower-most edge, which is engaging the rigid panel 4, will slide downthe panel 4, whilst the upper part of the pressure plate 13 continues tomove rearwardly, thus moving the lower-most ends of the depending arms12 to a rearward position in which they substantially abut the rearpanel 4. This enables the head-rest 5 to move forward sufficiently toengage the head of the occupant of the seat, to minimise or obviate therisk of a whiplash injury occurring.

[0030] Referring to FIG. 4 and FIG. 5, a vehicle seat 1 intended for usein a rear seat with the safety arrangement in accordance with analternative embodiment of the invention have a pressure plate 13′pivotally connected to lower ends of the depending arms 12 and carriedat the lower ends of the depending arms 12. The pressure plate 13′extends upwardly and downwardly from the pivoting axis. The pressureplate is in ordinary use held in a position relative the depending arms12 by deformable bands 21. As for the embodiment shown in FIGS. 1, 2 and3 will, when a vehicle in which a seat with a safety arrangementaccording to the embodiment shown in FIG. 4 and FIG. 5 is mounted issubjected to a rear impact, the torso of an occupant be forced into theback-rest of the seat. The torso will then engage the pressure plate 13′and the combination of the pressure plate 13′, the parallel arms 12, thehorizontal bar 7, the arm 6 and the head rest 5 will pivot about theaxis of the bar 7 such that the head rest 5 will begin to moveforwardly. Also for this embodiment the lower-most end of the pressureplate 13′ will strike the rigid panel 4 at the rear of the back-rest 3.Continuing pressure applied to the pressure plate 13′ by the torso ofthe occupant of the seat will cause the bands 21 to deform so that theupper part of the pressure plate will start to rotate about the pivotingaxis. As can be seen from FIG. 5 and FIG. 6, this means that thepressure plate 13′ will pivot about the pivoting axis. The lower part ofthe pressure plate that is engaging with the rigid panel 4 will slidedown whilst the upper part of the pressure plate 13′ continues to moverearwardly, thus moving the depending arms 12 to rearward position inwhich they substantially abut the rear panel 4. This enables the headrest 5 to move forward sufficiently to engage the head of the occupantof the seat, to minimize or obviate the risk of a whiplash injuryoccurring.

[0031] It is to be appreciated that the described movement of thehead-rest being effected against a bias provided by the springs orresilient means, if provided

[0032] In a further embodiment of the invention the head-rest and thedepending parallel arms are mounted on a horizontal rotatable bar whichextends between the two vertical parallel arm members that form theframe in the back of the seat. The rotatable bar itself forms thetransverse part of the inverted “U” shaped frame.

[0033] In the present Specification “comprise” means “includes orconsists of′ and “comprising” means “including or consisting of”.

1: A safety arrangement for a motor vehicle, the safety arrangementcomprising a head-rest, means to mount the head-rest for pivotalmovement about a first predetermined horizontal axis adjacent an upperpart of a back-rest of a seat, and depending means adapted to extenddownwardly within the back-rest of the seat beneath the firstpredetermined axis, and which carry a pressure plate to be locatedwithin the back-rest at a position behind a torso of an occupant of theseat, so that pressure applied to the pressure plate will cause thehead-rest to move, the pressure plate being pivotally connected to thedepending means. 2: An arrangement according to claim 1 wherein thedepending means comprise parallel arms. 3: An arrangement according toclaim 1 wherein the pressure plate is provided with an integral locatingelement extending upwardly above a second axis about which the pressureplate is pivotally connected to the depending means, the locatingelement being releasably connected to the depending means. 4: Anarrangement according to claim 3 wherein the locating element isconnected to the depending means by means of at least one spring clip.5: An arrangement according to claim 3 wherein the locating element isconnected to the depending means by means of at least one frangibleelement. 6: An arrangement according to claim 1 wherein a locatingelement is arranged in association with the pressure plate and thedepending means in a position above a second axis about which thepressure plate is pivotally connected to the depending means. 7: Anarrangement according to claim 6 wherein the locating element isdeformable. 8: An arrangement according to claim 1 wherein the means tomount the head-rest comprise a substantially horizontal bar adapted tobe mounted, by means of bearings, on a frame within the back-rest of theseat, an axis of the horizontal bar being the said first predeterminedaxis, the head-rest being connected to the bar. 9: An arrangementaccording to claim 8 wherein the depending means are connected to anddepend from the bar. 10: An arrangement according to claim 1 wherein arear of the back-rest is provided with a rigid panel. 11: A safetyarrangement for a motor vehicle, the safety arrangement comprising: ahead-rest; a substantially horizontal bar rotatably mountable in anupper part of a back-rest of a seat, the head-rest mounted to thesubstantially horizontal bar such that the head-rest can be pivotallymoved about the substantially horizontal bar; at least one depending armextending downwardly from the substantially horizontal bar, the at leastone depending arm capable of being positioned within the back-rest ofthe seat; and a pressure plate for placement behind a torso of anoccupant of the seat, the at least one depending arm pivotally connectedto the pressure plate such that pressure applied to the pressure platewill cause the head-rest to move. 12: An arrangement according to claim11, wherein the at least one depending arm comprises two parallel arms.13: An arrangement according to claim 11, wherein the pressure plate hasan integral locating element extending upwardly above an axis aboutwhich the pressure plate is pivotally connected to the at least onedepending arm, the locating element being releasably connected to the atleast one depending arm. 14: An arrangement according to claim 13,wherein the locating element is connected to the at least one dependingarm by at least one spring clip. 15: An arrangement according to claim13, wherein the locating element is connected to the at least onedepending arm by at least one frangible element. 16: An arrangementaccording to claim 11, wherein a locating element is arranged inassociation with the pressure plate and the at least one depending armin a position above an axis about which the pressure plate is pivotallyconnected to the at least one depending arm. 17: An arrangementaccording to claim 16, wherein the locating element is deformable. 18:An arrangement according to claim 11, wherein the substantiallyhorizontal bar is mountable, through the use of bearings, on a framewithin the back-rest of the seat. 19: An arrangement according to claim11, wherein a rear of the back-rest is provided with a rigid panel.